U.S. Pat. No. 4,534,743 issued Aug. 13, 1985, to Anthony D'Onofrio and Walter Kitik describes a process for making flexible split-electrode electroluminescent lamps by applying required lamp component layers in succession on a carrier strip which itself becomes part of the lamp. The disclosed process involves depositing a slurry of uncured epoxy resin and electroluminescent phosphor particles on a transparent conductive coating (indium-tin oxide) previously applied to a transparent flexible insulating carrier strip (MylarR strip). The slurry coated strip is passed through a curing oven to cure the epoxy resin to bond the phosphor particulate in a flexible matrix and to adhere it to the coated carrier strip. Then, a slurry of liquid-borne conductive particulate is continuously deposited on the cured strip and the slurry dried to provide a second continuous coating of electrically conductive material; e.g., a nickel-filled acrylic coating. The laminated panel is then subjected to the split-electrode forming steps described in the patent. In the embodiment shown in FIGS. 7-10 of the patent, the transparent first conductive layer on the carrier strip is shielded in areas across the strip and a single electroluminescent slurry layer is applied between shielded areas, leaving side strips of the first conductive coating exposed for contact with separate electrical connector members. Copending application Ser. No. 940,794 entitled "Method for Manufacturing An Electroluminescent Panel Lamp As Well As Panel Lamp Produced Thereby" filed Dec. 12, 1986, now abandoned and of common inventorship herewith describes a method for making an electroluminescent panel wherein either dry phosphor particulate or a phosphor slurry is deposited on a first dielectric phosphor covering either a front or rear electrode layer on a moving carrier strip. The dry phosphor particulate is electrostatically deposited followed by deposition of a second dielectric layer over the phosphor layer. The first and second dielectric layers are cured by U.V. radiation to encase the phosphor in a dielectric mass. The other electrode of the electroluminescent panel is placed adjacent the cured second dielectric layer; e.g., the other electrode can be vapor deposited on the cured second dielectric layer.
Other prior art workers have used a different process to manufacture individual electroluminescent lamps on a non-continuous basis in that a continuously moving carrier strip is not used during the entire manufacturing process. In particular, prior art workers have deposited barium titanate in a solvent based slurry on a moving aluminum foil in a continuous process. The deposited barium titanate layer or coating is thermally cured. Phosphor in a solvent based slurry is then deposited on the cured barium titanate layer in a continuous process as the foil moves. The phosphor slurry is then cured using thermal curing. The foil is then cut into sections or pieces about 12 inches by 12 inches and a slurry of transparent indium tin oxide (ITO) is deposited in areas that are to become lamp elements on each section by silk screening followed by a thermal cure. A bus bar is deposited on each ITO coated area by a slurry and silk screening process and thermally cured. Individual lamp sections that in FIG. 1 hereof are the united elements 17, 19, 21, 23, and 27 are then cut or separated from the large sections. A front electrical lead is attached to the bus bar and a rear electrical lead is attached to the rear foil. Final assembly involves placing a front plastic cover over the bus bar and ITO layer with a dessicant layer therebetween and a rear plastic cover over the rear foil electrode. The front and rear plastic covers are tack welded at several places and the assembly then is stored in a dry room (humidity of 10% and temperature of 120.degree. F.) for three days. Following drying, the edges of the front and rear plastic covers are heat sealed around the entire periphery. FIG. 1 illustrates such an electroluminescent lamp construction comprising a front plastic cover 11, a dessicant layer 13, transparent front ITO electrode 17, phosphor layer 19, reflective barium titanate layer 21, rear aluminum electrode 23 and rear plastic cover 25. Bus bar 27 is attached to front electrode 14' and front lead 9 is attached to the bus bar. Rear lead 7 is attached to foil electrode 23. U.S. Pat. No. 2,728,870 describes a process for increasing light output of an electroluminescent lamp by heating the cured resin/phosphor layer after deposition on a substrate to the melting temperature of the resin while subjecting the heated layer to a D.C. electric field to impart a common alignment to the phosphor particles after cooling of the layer.
Technical article entitled "High Brightness Electroluminescent Lamps of Improved Maintenance" published by R. J. Blazek in Illuminating Engineering, November, 1962, provides information on construction of electroluminescent lamps and factors affecting their brightness or light output.
Similarly, a technical article entitled "Lasers, EL, and Light Value" published in Display systems Engineering, pp. 379-391, 1968, discusses factors which affect performance of electroluminescent lamps.